Biofuel (currently defined as ethanol) production in the U.S. will require the development of alternative biomass sources if the U.S. is to meet the goal in the U.S. Energy Security Act of 2007 to derive 30% of its petroleum from renewable sources.   Several different groups of biomass crops are currently in development to meet these needs.  Sorghum (Sorghum bicolor L. Moench) is one such crop that will be an important feedstock source for biofuel production.  As composition influences productivity, there a need to understand the range in composition observed within the crop.  The goal of this research was to assess the range in dietary fiber composition observed within different types  of biomass sorghums.  A total of 152 sorghum samples were divided into the four end-use type of sorghum; biomass, forage, sorghum/sudangrass, and sweet.  These samples were analyzed chemically analyzed using dietary fiber analysis performed at the National Renewable Energy Laboratory using published protocols.  Significant variation between the groups was detected for glucan and ash.  Positive and highly significant correlations were detected between structural carbohydrates in the biomass and sweet sorghums, while many of these correlations were negative or not significant in the forage and sorghum/sudangrass types.  In addition, a wide range of variation was present within each group indicating that there is potential to manipulate the composition of the crop.